wiring main panel

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Old 12-16-07, 12:56 AM
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wiring main panel

I have almost completed wiring my new home (with greatly appreciated help from this forum). I have been procrastinating wiring the main panel due to lack of confidence (obviously not the place to make a boo boo) and lack of a good diagram on exactly how to wire the main laterals, neutral, equipment ground, and bonding.
The local REA installed a new meter pedestal (80' from house) including a 200 amp breaker and a couple of spaces for additional breakers including breaker for the well pump at the pedestal. I have run the service lateral into the main panel in the garage (Square D Homeline 40/40), and have run all the home runs to, but not into the panel, and installed ground system with ground to, but not into the panel.
The main panel has a 200 amp main disconnect with lugs for the two hot legs, and a large lug (for neutral?) on the cross bar (neutral bar) as well as a smaller lug on the cross bar that appears to be a lug for the ground, but I'm not sure. The panel also has two neutral bars and I have install two ground bars (one on each side) to make the individual circuit breaker wiring easier and neater.

I guess what I'm asking is where can I find a diagram for wiring this panel? I have some books on wiring and have searched the internet including this site and the Square D site but I can't seem to find what I'm looking for. Can someone draw me a picture or provide directions to a reference for wiring the panel? I think I understand most of it (wiring the hots, the neutral and the circuit breakers), but would feel much more confident if I had some instructions. For example, can I go directly into the hot lugs on the main with the laterals (bottom feed) or do I need to make a loop or curve with the wire to provide some slack for expansion and contraction?

The lateral isn't wired to the meter pedestal yet either. While it looks straight forward, any help there would also be appreciated, although the REA I'm sure would be willing to show me how to do it.

Thanks
Tim
 

Last edited by mulligan; 12-16-07 at 01:03 AM. Reason: add last paragraph
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Old 12-16-07, 01:59 PM
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Originally Posted by mulligan View Post
The local REA installed a new meter pedestal (80' from house) including a 200 amp breaker and a couple of spaces for additional breakers including breaker for the well pump at the pedestal. I have run the service lateral into the main panel in the garage (Square D Homeline 40/40), and have run all the home runs to, but not into the panel, and installed ground system with ground to, but not into the panel.


a reference for wiring the panel? I think I understand most of it (wiring the hots, the neutral and the circuit breakers), but would feel much more confident if I had some instructions. For example, can I go directly into the hot lugs on the main with the laterals (bottom feed) or do I need to make a loop or curve with the wire to provide some slack for expansion and contraction?

The lateral isn't wired to the meter pedestal yet either. While it looks straight forward, any help there would also be appreciated, although the REA I'm sure would be willing to show me how to do it.

Thanks
Tim
Tim,
who is REA?? you need to talk to them.

first off is this pedestal you speak of a temporary service meant for construction.. or is this your meter socket/main breaker panel for your house service.

If it is a meter/main breaker panel, you need to sub feed the panel in the house.

Another words... your 200 amp main breaker for the house is in the pedestal panel. you then need to run four wire from there into the garage to the sub panel. They have service entrance cable that is called four conductor SER #4/0 gauge that is good for 200 amps. The homeline 40/40 you have in there is a main breaker panel. You don't need the main breaker in that panel. The breaker in the pedestal panel is protecting your wiring to the sub panel and the branch circuit breakers. All you need is a 200 amp 40 space main lug panel.

The neutral wire (white) goes to the neutral buss in the main lug panel and is a floating neutral( the buss is isolated from the cabinet). All branch circuit 120 volt neutral wires(white insulated) connect to the neutral buss in the sub panel which goes all the way back on the white service wire to the main breaker meter panel before being bonded.

You then add the ground buss bars like you did and all bare grounds connect to that. The Green service wire is attached to the ground buss bar and that buss is bonded to the sub panels enclosure then goes back to the pedestal
 
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Old 12-16-07, 06:33 PM
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Brewaholic,

REA stands for rural electric association, in my case it is Vigilantee Electric. The meter pedestal is the permanent meter socket with a main breaker. Vigilantee, and my electrical inspector both have told me it is fine (even preferrable) to have a second main disconnect in the house and the inspector has seen my 3 wire (4/0, 4/0, 2/0) service lateral and was fine with it. I do infact have a 100 amp sub panel in the house fed by the main panel in the house with a 4 wire SER cable as you describe.

Tim
 
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Old 12-17-07, 09:30 AM
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Originally Posted by mulligan View Post
Brewaholic,

REA stands for rural electric association, in my case it is Vigilantee Electric. The meter pedestal is the permanent meter socket with a main breaker. Vigilantee, and my electrical inspector both have told me it is fine (even preferrable) to have a second main disconnect in the house and the inspector has seen my 3 wire (4/0, 4/0, 2/0) service lateral and was fine with it. I do infact have a 100 amp sub panel in the house fed by the main panel in the house with a 4 wire SER cable as you describe.

Tim

very interesting that the inspector would like to see two main breakers on a system.
Where does he want the earth ground? what breaker panel will be the ground fault panel? Is he saying he wants two earth grounds?

you need to talk it over with him on your game plan

If the 100 amp is sub fed, then you need to wire that like I told you for the garage panel with the white neutrals floating and the bare grounds separated and bonded to the sub.

The garage panel if he will let you wire that as a main breaker panel?

If you look at the seu 4/0 4/0 2/0 the two 4/0's are black and black with white trace.

Low voltage 208-250vac phase wiring colors are Black = A phase, Red = B phase, and Blue = C phase white is neutral and green or bare ground. the 100 amp sub panel ser wire will be marked like above and should be wired to the 100 amp breaker in the same manor

If it is aluminum wire you need to use anti oxide paste, commonly known as "no alox" on all the service wire terminal connections.

Since it is single phase, you dont have the three hots, but you still should follow the colors, So Black is the A and Red or in your case with seu cable Black with White tracer is the B phase.

Left side of the main breaker gets the black, Right side gets the black/white. you do this out at the pedestal also.

neutral wire goes to the neutral buss. In the screw kit that came with the panel there is a bonding jumper and screw.

You slide the jumper into one of the neutral buss terminals that has the threaded screw hole in the panel to accept the bonding screw next to the buss. then install the bonding screw and tighten the buss lug terminal.

This bonds the neutral bars to the panel then the earth ground rod which is usually driven very close to the main breaker panel goes to the neutral buss via # 4 solid bare copper ground wire.
All neutral wires and bare grounds get hooked up to the neutral buss in the main breaker panel.

Then you'd need to run your cold water ground wire to the nearest cold water copper pipe. #4 bare copper is used there also. Then anywhere you would disconnect an appliance that would break the bond between hot and cold water piping, you need a jumper of #4 copper.

Like on the hot water heaters supply pipes if copper. two cold water ground clamps and a piece of #4 bare copper between the hot and cold pipe. That way if the appliance is removed you still have a bonding ground. They also want you to jumper a city water meter if you had one for bonding purposes.

If a hot wire ever touches the pipe(s, a ground fault occurs and trips the circuit breaker.

As far as drip loops in the panels it depends on if they come into the panel from above or below if from above then you need to povide a drip loop on the conductor. 4/0 can be fun to work with for drip looping, 500mcm is another story!

Talk to that inspector and see exactly what he wants as far as ground rods(earth ground)
 
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Old 12-18-07, 09:53 AM
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The inspector preferred that I have the second main breaker because of its accessibility (in house/garage) compared to the one at the panel 80 feet away outside. The earth ground is at the garage main panel and was already in when he inspected. He was happy with it.

What is still a little confusing to me is the terminology: "neutral buss" is that just the verticle busses (with the screws) on each side of the panel? If so what is the flat bar that runs horizontally between the two sides called? And why is there two lugs (one large) one small on this flat bar if I'm supposed to connect the neutral and ground to the vertical busses?
 
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Old 12-18-07, 10:34 AM
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Originally Posted by mulligan View Post
The inspector preferred that I have the second main breaker because of its accessibility (in house/garage) compared to the one at the panel 80 feet away outside. The earth ground is at the garage main panel and was already in when he inspected. He was happy with it.
Good then you are fine with wiring the garage as a main breaker service panel

What is still a little confusing to me is the terminology: "neutral buss" is that just the verticle busses (with the screws) on each side of the panel?
yes these two verticle busses are the neutral/ground buss in a main breaker panel

all of your neutrals and bare ground get connected to these


If so what is the flat bar that runs horizontally between the two sides called? And why is there two lugs (one large) one small on this flat bar...... I'm supposed to connect the neutral and ground to the vertical busses?
that flat bar ties the two busses together when you use this panel as a main breaker panel.

you can remove that if you needed to isolate the neutrals from the grounds like in sub fed panels.

the bonding jumper I described in the other post would be used on just the one side, then the bare grounds would connect to that buss. the green wire would connect to this side

the other side would not be bonded to the panel (floating neutral buss) and the insulated neutral wires would hook to that then you put the neutral white wire feed on this side

As it is now...
The large lug on the flat connector bar is for the neutral wire.. The small lug is for the ground rod, or cold water ground wire connection

remember you need a cold water ground and the earth ground connected to the panels neutral/ground buss for grounding and bonding purposes

Only one conductor is allowed under one lug.. the other ground wire will need to go on one of the larger terminals on the vertical busses



when you wire the panel the service feeds and ground bond wires are installed first

a tip when wiring the branch circuits

When you have all the sheathing stripped and the wire connectors connected into the panel

start with your grounds first and connect those to the buss. bend all white and hots out of your way while installing the grounds.

then you cut to length and strip the white neutral wire end enough to connect to the lug and install all those.

you are now left with your hot wires to install into the breakers. this way your bare grounds are in the back of the panel with little chance of hitting a hot wire terminal when energized
 

Last edited by brewaholic; 12-18-07 at 11:38 AM. Reason: added more info
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Old 12-18-07, 11:05 AM
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Adhere to a "color-code" when terminating the Black / Red conductors on the breakers.

Indentify the Service Conductor (SC) that terminates on the right lug of the MCB with red marking tape.

Determine which one of the two vertical busses connects to the "Red" SC--- this is a simple continuity test done with a multi-meter.

Connect all Red wires to the "red" bus -- some Black wires may have to connect to the 'red" bus in order to "balance" circuits feed by 2-wire cables.Ex; two 2-wire cables to two AC window units -- one Black wire to the "red" bus , and the other to the "black " bus

You MUST indentify, on the panel-cover, which loads are connected to the breakers. Also, have a seperate table you can refer to in the future, which lists as exactly as possible what outlets ( receptacle/ fixture ) and loads are connected to each breaker.

Good Luck , & Learn & Enjoy from the Experience!!
 
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Old 12-19-07, 08:56 PM
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Thanks for the input, it has been quite helpful! I have never wired anything before except changing light fixtures, and wiring a complete house has been quite an adventure. But I have been really enjoying it. Having this site to refer to has been a big help!
 
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Old 12-20-07, 01:14 AM
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Brewaholic, just for your information...where 2005 NEC 230.70A1 and 2006 IRC E3501.6.2 says "...readily accessible location either outside of a building or structure or inside nearest the point of entrance of the service conductors." it is generally interpretted to mean immediately outside the building or actually mounted on the exterior wall. Also, there is no violation of Code to have main breaker sub-panels. Main lug only panels are only used to save money. The grounding electrode is always required to be installed at the service entrance panel or electrical point of entry (2005 NEC 250.24A and 2006 IRC E3507.2).
 
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Old 12-20-07, 07:56 AM
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Originally Posted by kqresq View Post
Brewaholic, just for your information...where 2005 NEC 230.70A1 and 2006 IRC E3501.6.2 says "...readily accessible location either outside of a building or structure or inside nearest the point of entrance of the service conductors." it is generally interpretted to mean immediately outside the building or actually mounted on the exterior wall. Also, there is no violation of Code to have main breaker sub-panels. Main lug only panels are only used to save money. The grounding electrode is always required to be installed at the service entrance panel or electrical point of entry (2005 NEC 250.24A and 2006 IRC E3507.2).
the problem is that inspectors do not like to see more the one main breaker on any one service. They want the ground rods driven at the service main.. the closer the better for ground fault.

They don't want multi points for grounding on residential in our area. So if the service drop or laterial is pulled to the meter socket (utilities responsibility to socket)they want a fused disconnect protection as close to that socket for the wires feeding the panel (residents responsiblity from socket in).

on the pedestal in this case has a main breaker panel there that controls his well pump and I guess the house

our inspectors would make you use that as the main panel and sub feed (four conductor)all other points back to this panel so if a ground fault would occur it would fault to earth ground at this point
 
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